Introduction

What if the world is in depression - again? Any talk of a 'slowdown' now seems risible. Talk of a possible 'technical recession' has come and gone. Even sound bites about the 'credit crunch' do not measure up. 'Recession' has been officially acknowledged - meaning at least two consecutive quarters of decline - in one after another of the major economies. So we have become accustomed to the phrase, from economists, business leaders and politicians alike, that this looks like the worst scenario 'since the Great Depression of the 1930s'. But what if this is actually a depression of that magnitude? Whatever can we do about it? How on earth can we understand it?

We can start by learning from what happened before. If we are short of ideas ourselves, we may have a new interest in the ideas that came out of the last epoch of depression, unemployment and uncertainty. One name above all keeps on cropping up, not only when economists discuss the situation but in the columns of British and North American newspapers and magazines, and in other media commentary. Often there is a grainy picture of a tall, stooped man with a pasty face, watery eyes, thinning hair and a heavy moustache, a half-familiar figure from a former era of worldwide economic depression - an era that closed when the Second World War peremptorily intervened. It's Keynes, of course. But who was he and why does his thinking matter to us now?

His is an extraordinary reputation. Through nine decades, he has been celebrated, scorned, respected, appropriated, mocked, venerated, derided, rediscovered - but seldom ignor